kyphosis {rpart} | R Documentation

## Data on Children who have had Corrective Spinal Surgery

### Description

The `kyphosis` data frame has 81 rows and 4 columns. representing data on children who have had corrective spinal surgery

### Usage

    data(kyphosis)

### Format

This data frame contains the following columns:

`Kyphosis`
  a factor with levels `absent` `present` indicating if a kyphosis (a type of deformation) was present after the operation.
`Age`
  in months
`Number`
  the number of vertebrae involved
`Start`
  the number of the first (topmost) vertebra operated on.

### Source

John M. Chambers and Trevor J. Hastie eds. (1992) Statistical Models in S, Wadsworth and Brooks/Cole, Pacific Grove, CA 1992.

### Examples

    data(kyphosis)
    fit <- rpart(Kyphosis ~ Age + Number + Start, data=kyphosis)
    fit2 <- rpart(Kyphosis ~ Age + Number + Start, data=kyphosis,
                  parms=list(prior=c(.65,.35), split='information'))
    fit3 <- rpart(Kyphosis ~ Age + Number + Start, data=kyphosis,
                  control=rpart.control(cp=.05))
    par(mfrow=c(1,2))
    plot(fit)
    text(fit, use.n=TRUE)
    plot(fit2)
    text(fit2, use.n=TRUE)

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